Automatic telephone system



July 24, 1934. J, w c s 1,967,848

AUTOMATIC TELEPHONE SYSTEM Fil March 19, 1917 2 Sheets-Sheet 1 HZZQLEQLJ[ILL/BRIEF July 24, 1934. J. wlcKs 4 AUTOMATIC TELEPHONE SYSTEM FiledMarch 19, 1917 2 ShfetS-Sheet 2 EN F [UL/517227? Patented July 24, 1934PATIENT OFFICE AUTOMATIC TELEPHONE SYSTEM John Wicks, Chicago, Ill.,assignon by mesne assignments, to Associated Electric Laboratories,Inc.-, Chicago, 1ll.,'a corporation oi Delaware Application March 19,1917, Serial No. 155,040 I 41 Claims. (01.179-27) My invention relatesin general to automatic telephone systems, but'is more particularlyapplicable to 'automatictoll service trunking systems, such for exampleas the one disclosed in my prior application, Serial No. 124,358, issuedas Patent No. 1315,444, Sept. 9, 1919; and the object of the inventionis toprovide an improved automatic ringing system of maximum convenienceand efliciency.

The particular arrangement employed, its advantages, and its intendedmode of operationwill be fully described hereinafter, reference beinghad to the accompanying drawings, comprising Figs. 1 and 2, which showin diagrammatic form the essential circuits of a system embodyingtheprinciples of my invention.

For a clear understanding of the drawings they should be placed in orderwith the lines at the ends thereof in alignment, and when thus arrangedthere is shown a complete circuit connection extending from a tolloperator's cord'circuit to a local subscriber. The connection has beenestablished through the medium of elements of a toll service trunkingsystem comprising a toll first selector V (the circuits of which are notshown), a tollsecond selector W, and a combi nation toll and localconnector H.

Inasmuch as a complete disclosure of the general purpose and utility ofa toll service trunking system of the character-shown in the drawingshas been made in my prior application above referred to, it will beunnecessary to encumber this application with another. It may bementioned briefly, however, that each toll operator is given access to asystem of toll service trunks by means of which she is enabled toconnect toll lines with the lines of local subscribers. For example, andreferring to the drawings the operator who has the toll cord circuit 0,has in front of her a plurality of jacks, one of which is the jack J,from which trunk lines extend to toll first selectors, one of which isthe selector V. The toll first selectors have access to trunk linesterminating in toll second selectors, such as the selector W; and thetoll second selectors in turn have access to trunk lines which terminatein connectors such as the connector H. If desired, and it is soillustrated in the drawings, the toll second selectors may also beaccessible to incoming toll selector repeaters; while the connectors maybe accessible in common to toll second selectors and the secondselectors of the regular local trunking system.

The cord circuit 0, of which only the local end is shown, may be of anyapproved long discord circuit O'is located desires to call the linetance type, except for certain modifications which will be mentioned,and comprises the usual tip-and ring talking strands terminating in theplug P, a combination ringing and listening key K, and a supervisorylamp L controlled by the 9- supervisory relay 2-. The key K is a callingdevice key and when actuated serves to substitute the calling device CDfor the supervisory relay 2 in the sleeve of the cord circuit. Thecalling device CD may be of any well known two-wire 5 type, such forexample as is shown in the British patent to Dicker, #29,654 of 1910;and in addition to the usual break impulse springs is provided with apair of springs 5 and 6 which are allowed to make contact whenever thedial of the device is turned from its normal position. The function ofthe relays 3 and 4 is to'start the automatic ringing of the calledsubscriber, as will be fully explained hereinafter.

The selector and connector switches in the system are of the well knownStrowger vertical and rotory type, the mechanical construction of whichis disclosed in the U. S. patents, to Keith, Erickson, and Erickson,Nos. 815,321, and 815,176, bot-h granted March 13, 1906. In the selectorswitches, however, the side switches and private magnets have beenomitted, and all circuits, including the connector circuits, have beenrevised in accordance with modern two-wire practice. Further circuitmodificationsrelating to the adaptation of the switches for use in atoll service trunking system, and to the incorporation in such a systemof my improved automatic ringing arrangement, will be described indetail in the description of the operation.

The called substation A, the individual line switch C, and the masterswitch D are of the usual construction and are described and theirfunctions explained in the U. S. patent toNewforth, No. 13,901, reissuedApril 13, 1915. While I have shown throughout the drawings a pluralityof batteries it is to be understood that there is preferably but onebattery having its positive pole grounded. Anexception to the aboveisthe batteryB' associated'with the ringing interrupter IR, which isprovided to insure the operation of the ring-cut-oif relay in theconnector when the called subscriber answers. The reference character Qindicates a busysignaling machine. I W

Having described briefly the apparatus in- -volved, I willnow proceed toexplain the operation of the same, it being assumed for this purposethat the toll operator at whose position the 1m off-substation A tocomplete a toll connection therewith. v.In the following explanation theoperation of the toll first selector V will be neglected entirely andthe operations will be considered as though the jack J was connecteddirectly with the toll second selector W, as, in fact, it might well be.

Assuming that the cord circuit 0 is to be used in establishing theconnection, the operator, after first observing that the toll servicetrunk with which the busy lamp L is associated is idle, as indicated bythe unlighted condition of the said lamp, will insert the plug P intothe jack J of the service trunk. Upon the insertion of.

the plug in the jack a control circuit for the line relay 29 of the tollsecond selector W is completed over the following path: Ground at Gwinding of supervisory relay 2, contact springs 12 and 13 of the callingdevice key K sleeve of plug P, sleeve of jack J, conductor 52, armature54 and its resting contact, and the windin of line relay 29 to batteryB". Upon the comp etion of the above circuit, relays 2 and 29 areenergized in series, the former relay closing a. circuit for-thesupervisory lamp L in an obvious manner. Relay 29, upon energizing,completes a circuit for the slow-acting release relay 30,

which relay, upon energizing in turn, prepares a circuit for thevertical magnet 35 in the usual manner, and also closes a circuit forthe busy lamp L and its multiples at other operators positions over thefollowing path: Ground at G,

working contact of armature 55 and the said armature, conductor 51, andthe lamp L' to battery B By the illumination of the busy lamps, theother operators are warned that the service trunk terminating in thejack J has been taken for use. A branch of. the. above circuit extendsover conductor 51', to the test contact 56' and its multiples in thebanks of the toll selector repeaters having access to the toll secondselector W, where by a ground potential on these test contacts, the saidselector is made busy.

The foregoing operations have occurred in re sponse to the insertion ofthe plug in the jack. The operator may now proceed to dial the number ofthe wanted subscriber, but before so doing, she is required first tooperate the calling device key the actuation of which results in thesubstitution of the calling device CD for the supervisory relay 2 in thecircuit of the relay 29 of the selector. When now the calling device isactuated in accordance with the first digit of the required number, aseries of interruptions is produced in the circuit of the line relay 29.Responsive to these interruptions of its circuit, the line relay 29deenergizes a corresponding number of times and at each "deenergizationsends an impulse to the vertical magnet 35 over the following path:Ground at G, armature 57 and its resting contact, resting contact ofarmature 58 and the said armature, armature 59 and its working contact,winding of low resistance relay tacts in which terminate trunk linesextending to a group of connectors which have access to the line ofsubstation A. The relay 31 is energized in series with the verticalmagnet, and being slowacting retains its armature attracted during theseries of impulses. At the first upward movement of the shaft, theoff-normal springs '75 are permitted to close, thereby completing aninitial energizing circuit for relay 32 as follows: Ground at G, workingcontact of armature 55 and the said armature, armature '72 and itsworking contact, off-normal springs 75, and the winding of relay 32 tobattery B Upon energizing, relay 32 closes a locking circuit for itselfover the following path: Ground at G, interrupter contact of the rotarymagnet 34, off-normal springs 75, and the winding of relay 32 to batteryB As a further result of its energization, relay -32 prepares at itsarmature 73a circuit for the rotary 'magnet 34 which, however, is heldopen during the vertical movement of the switch by the slow-acting relay31. At this point it should be mentioned that as soon as the off-normalsprings 75 are closed, the line switching relay 25 is connected inseries with the relay 32 over the following circuit: Grounded conductor51, wind ing of the said relay 25, interrupter contact of the rotarymagnet 34, off-normal springs 75, and the winding of relay 32 to batteryB It is noted however, that first ground G and then ground G have beenconnected to this circuit at points midway in the circuit connecting thetwo relays; whence it follows that the relay 25 is short-circuited andremains inoperative for the present.

At the end of the series of impulses the slowacting relay 31 deenergizesand completes a circuit for the rotary magnet 34 as follows: Ground at Gworking contact of armature 55 and the said armature, armature '72 andits resting contact, working contact of armature 73 and the saidarmature, and the winding of rotary magnet 34 to battery B The rotarymagnet 34 is energized over the above circuit and rotates the switchshaft one step, thereby bringing the wipers 90 to 93, inclusive, intoengagement with the first set of contacts in the level opposite whichthey were raised. Near the end of its stroke the rotary magnet separatesits interrupter contact, thereby breaking the circuit connecting relays25 and 32 and opening the locking circuit of the latter relay.

Relay 32, therefore is deenergized and breaks the circuit of the rotarymagnet which deenergizes in turn and again closes its interruptercontact. The operation now depends upon whether or not the first trunkline is busy. If this trunk line is busy, the test contact with whichthe test wiper magnet 34, resulting in the advance of the switch Iwipers another step. It will be seen then that the relay 32 will operateas an impulse sender or stepping relay to advance the switch wipersthrough the medium of the rotary magnet as long as the test wiper 91continues to engage grounded test contacts. As soon as the firstungrounded test contact isreached, assumed to be the test contact 95,and the rotary magnet 34 deenergizes to close its interrupter contact,the relay 25 will no longer be short-circuited but will instantlyenergize in series with the relay 32 over the circuit previously traced.Relay 25 is of such high resistance, that relay 32 remains inoperative.Upon of armature 63and connects it instead to armature '64 of relay 26;at its armatures 61 and 62 prepares circuitsincluding the right handrepeating coil windings which will later be explained in detail; and atits armature completes-a control circuit extending to the line relay 100of the connector H (Fig. 2), which may be tracedasfollows: Ground at G,armature 5'7 and its working contact, working contact of armature 60 andthe said armature, wiper 92, bank contact 96, conductor 122, upperwinding of relay 106, upper contacts of the answering bridge orreversing relay 102, and the upper winding of line relay 100 to batteryB Relays 106 and 100 are energized in series upon the closure of theabove circuit and the relay 100 completes in the usual way an energizingcircuit for the slow acting release relay 101. Upon attracting itsarmatures, the s relay 101 prepares a circuit for the vertical magnet109 at its armature 132, and at its upperarrnature connects ground G tothe conductor 124, whereby a busy potential'is established on the testcontact 125 and its multiples in the banks of the local second selectorshaving access to thejconnector H. Sameground also extends byway of thewinding of relay lo'land the conductor 121 to test contact 95 and itsmultiples in the banks of the toll second selectors, whereby theconnector H is also made busy to'remaining toll second selectors. Thefunction of the relay 106, which it will be remembered was energized inseries with the line relay 100, is to change the characteristics oftheconnector H from those of a local connector to those of a tollconnector.

To explain this briefly, it has been mentioned before, that theconnector H is accessible in common both to toll second selectors suchas the selector W and to local second selectors comprising part of theregular exchange trunking system. The circuits of the connector H arenormally in such condition that the connector will operate as a standardlocal connector, and when seized by a local second selector thesecircuits are not altered in any respect. When seized by a toll secondselector however, certain of the circuits, as for example, those havingto do with the signaling of the called subscriber and testing for a busyline are required to be altered and a relay is therefore inserted inseries with the operating lead in the toll second selector trunk toperform these alterations or circuit changes. This relay is the relay106, which is made slow acting so that it will not respond to impulsesreceived over the operating circuit in which it is included. In itsenergized position, relay 106 disconnects at its armature 137 the ringcut-ofi relay 105, used on local connections, and substitutes thereforea ring cut-off relay in the toll second selector W over a circuit whichwill be subsequently traced; and at its lower armature 138. changes thecharacteristics of the connector from one which will lock on busy to onewhich will cut thru when the called line becomes idle.

The foregoing operations have occurred in response to the calling of thefirst digit of the required number (or the second digit, assuming that afirst selector is included in the connection) Before proceeding withthejcalling of the remaining digits, it will be advisable to return tothe cord circuit first and consider certain operations which take placein response to the actuation of the calling device dial in accordancewith the digit of the called number which controls the operation of thetoll second selector W. It has been assumed in the previous explanationthat the tolloperater desires to have the automatic ringing of thecalledsubscriber begin immediately upon' completion of the connection, andthis being the case she will have her listening key K inoperated-position'as shown in-the' drawings. Now when the dial is turnedto cause the actuation of the toll second selector as previouslydescribed,

an energizing" circuit is completed for the relay 3 device returns tonormal position the contact springs 5 and 6 are separatedagain and thecircult of relay 3 is broken. Relay 3, upon'deenerg1zing, breaks thecircuit of relay 4, but this latter relay, being slow-acting, does notdeenergize at once, whereby for ashort interval the generator Gen isbridged across the tip and ring strands of I the cord circuit asfollows:Upper or tip strand of the cord circuit, armature 14 and its workingcontact, armature 1'7 and its resting contact, generator Gen, restingcontact of armature l6 and the said armature, and the working contact or"armature l5 and the said armature to the lower or ring strand ofthe'cord circuit. A flow of alternating current is thus set up over theline conductorsof the trunk extending to the selector W to'actuate thebridged alternating current relay 33. Upon energizing, the relay 33closes a circuit for relay 26 as follows: Ground at G contact andarmature of relay 33, and upper winding of relay 26 to battery B Relay26, upon energizing closes a locking "circuit foritself over thefollowing path: Ground at G working contact of armature 55 andthe saidarmature, armature 78 and its resting contact, armature '66 and itsworking contact, and the lower winding of relay 26 to battery B As afurther result of its energization, relay 26 disconnects the bridgedbattery supply relay 28 from the windings of the repeating coil, and forthe upper winding of the said relay 28 substitutes the slow acting relay27, thereby preparing a signaling circuit which will be described later.Relay 26 also disconnects battery B from the test wiper 91 at itsarmature 64.

We will return now to the connector H and consider its operation inresponse to the dialing of the two remaining digits in the desirednumber, whereby the connection is extended to the called line. When theoperator turns the dial of her calling device for the next digit in thenumber, a series' of interruptions is produced in'the circuit of theline relay29 of the toll second selector W Ground at G 2, armature 130and its resting con I tact, armature 132 and its working contact,windingof low resistance relay 103, winding of the vertical magnet 109,and the side switch wiper 156, in first position, to battery B Inresponse 'to these impulses the vertical magnet 109 is operated to raisethe switch shaft step-by-step, until the wipers 150, 151 and 152 arriveopposite the horizontal level of bank contacts in which are locatedcontacts which are terminals of the line of substation A. The relay 103is energized in series with the vertical magnet, and being slow-acting,retains its armature attracted during the series of impulses to close acircuit for the private magnet 158. At the end of the series ofimpulses, the relay 103 and the private magnet are deenergized thelatter controlling the side switch wipers 156 and 157 to advance them totheir secand position in the usual and well known manner.

The operator may now call the final digit in the required number,resulting in another series of interruptions in the circuit of the linerelay 29,

which are repeated as before into the circuit of the line relay 100. Nowhowever, the side switch 156 having been advanced to its secondposition, the line relay 100 transmits a series of impulses to therotary magnet 110 over a circuit substantially the same as the onedescribed in the case of the verticalmagnet 109. Responsive to theseimpulses the rotary magnet 110 rotates the shaft of the switch until thewipers 150, 151 and 152 engage the bank contacts 153, 154 and 155respectively, .in which contacts the wanted line terminates. The slowacting relay 103 is energized as before during the final series ofimpulses and (assuming that the called line is idle) advances the sideswitch wipers to the third position through the medium of the privatemagnet as before.

When the side switch wiper 157 comes into engagement with its thirdposition contact point, a circuit is completed for the cut-01f winding200 of the called line switch as follows: Ground at G, side switch wiper157 in third position, private wiper'151, bank contact 154, and cut-ofiwinding 200 of theline switch C to battery B By the energization of thecut-off winding of the line switch, the armature 201 is actuated todisconnect the line of substation A from its ground and batteryconnections in the line switch. Ground G also extends to multiples ofcontact 154 in the banks of the other connectors in the group, where bya ground potential on these contacts the line of substation A is madebusy. A branchof the above traced circuit extends through the winding ofthe wiper switching relay 108 by way of side switch wiper 156 in itsthird position to battery B The relay 108 is thereupon energized toextend the talking conductors of the connector through to the linewipers 150 and 152; and as a result of this operation, a signalingcircuit for actuating the ringer 202 at substation A is completed asfollows: Ground at G, generator Gen,

' contact of ringing interrupter IR, lamp L resting contact of armature140 and the said armature, resting contact of armature 136 and the saidarmature, armature 142 and its working contact, wiper 152, bank contact155, through the ringer 202 at substation A, bank contact 153,

wiper 150, working contactof armature 141 and the said armature,armature 134 and its resting contact, armature 137 and its workingcontact, trunk line conductor 120, bank contact 94, wiper 90, winding 79of the repeating coil, armature 62 and its working contact, armature 65and its working contact, and the winding of relay 27 to battery 3".Relay 27, owing to the provision of a slug of copper on its core, isslow to energize and does not respond to alternating current in theabove circuit.

Connection has now been established with the tery B for the generatorGen in the ringing circuit in order to produce an intermittent ringingof the bell at the called substation. In case the called subscribershould respond while alternating current is on the line, the relay 27at'the toll second selector will be energized by' current from thebattery B in series with the generator; but in case the receiver isremoved during a silent period, the said relay 27 will be energized bycurrent from the two batteries B and B in series. In any event, when thecalled subscriber takes 01f his receiver, relay 27 will be operated toopen the locking circuit of relay 26, resulting in the deenergization ofthe latter relay with the following results: At armatures 65 and 67 theanswering bridge 28 is bridged across the line circuit in series withwindings 79 and 80 of the repeating coil, and at armature 64 battery Bis connected to the test wiper 91. The relay 107 of the connector H isnow energized over the following circuit: Ground at G armature 131 andits working contact, winding of relay 107, conductor 121, bank contact95, wiper 91, armature 63 and its working contact, armature 64 and itsresting contact and the resistance, 77 to battery B Upon energizing,relay 107 closes at its armature 139 a circuit through the lowerwindings of relay 106 for a purpose to be described later; and at itslower armature 140 disconnects the lead extending to the ringingapparatus and closes a contact in the talking circuit, whereupon theanswering bridge relay 28 will become energized over the heavy lineconductors extending to substation A. This circuit, being for the mostpart drawn in heavy lines, need not be traced in detail.

The energization of relay 28 has the following results: At armature 70the alternating current relay 33 is disconnected from in bridge of theline conductors; at armature 69, the left hand windings of the repeatingcoil are connected to complete the talking circuit; at armature 68ground G is connected to the control circuit extending to the line relay100 of the connector H as a substitute for ground G removed an instantlater by the deenergization of relay 29, as will appear shortly; and atarmature 54 the conductor 52 is disconnected from the line relay 29 andis connected instead to the slow acting release relay 30. It should bementioned at this point that the line relay 29 is of moderateresistance, preferably 250 ohms, while the release relay 30 should be ofat least 1300 ohms resistance. The supervisory relay 2 at the cordcircuit is marginally adjusted so that it will energize in series withthe line relay 29 and will deenergize when connected in serieswithrelease relay 30. It follows then, that when the called subscriberanswers and the answering bridge relay 28 is energized by the processalready described, the resistance of the circuit including thesupervisory relay 2 at the cord circuit will be sufliciently increasedto cause the deenergization of the said relay and extinguishing of thesupervisory lamp L.- The operator isthussnotifled'that the called partyhas answered the telephone. The con nection to the other subscriber maythen be completed by means of the other plug uiot' shown) of thecordcircuit inthe-usual manner, and conversation between thetwoconnected subscribers may be 'held'over the heavy line conductors.The subscriber at substation A is-of course supplied with talkingcurrent through thewindings of the answering bridge relay 28 ofthe tollsecond selector W; while the other subscriber' may be supplied withtalking-current from connective apparatus associated with his lineduring the connection'in any suitable or desired'ma'nner.

When the conversation is flnishedj' the subscribers will replace theirreceivers. By the re-:

placement of the receiver at substation A the relay 28 at the tollsec'ond'selector is 'deener"- gized, whereby the linerelay 29 isagainconnected in thecircuit of the supervisory relay 2,

andthe 'latter relay isenergized'to illuminate the lamp L. Beinginformed 'b'y the lighting of l the lamp that the conversationterminated,

the operator will takefdownthe'cord circuit, the

' removal of iplug P from jack J being effective to break the circuit ofthe line'relay 29 of the selector W. The consequent deenergization ofline relay 29 is followed by-the deenergization' of the release relay30,and results also in the breaking of the control circuit including theline relay 100* of the connector H.- B'y the former operation ground Gis 'disconnected from'conductor 5l whereby'thebusy-lamp L and itsmultiples are extinguished, andthe'circuit of the line switch relay25 isbroken-to' permit it to de--* energize. At the same time -a circuitis-closedfor the release magnet 36 of the-"selector over' the followingpath: Groundat'Ga'armature 57 and its resting contact, resting contactof armature 58 and the said armature, armature '59 and its restingcontact, off 'normalsprings' 76, and the windings: of the release magnet36 to battery B By the energization'of-"the'release magnet,

the selector W is restored to normal position in xtheusual and wellunderstoodmanner; "the re lease magnet circuit being opened'at the oifnor-- mal springs 76 when'the shaft reaches its lowermostposition. Atthe connector H, the deenergization of the line relay l00'is followed bythe deenergization of the release-relay 101. When relay 101 retracts itsarmatures, ground (2& is disconnected from the multiple testcontacts inthe selector banks and is connected instead to the release'magnet 159,whereupon the connector H is restored to normal position insubstantially the same manner as was described in the case of the secondselector "W.-"The circuit through the lower winding of relay 106 isprovided'to guard against a momentary ringing of the'called subscriberduring the release of the connector. This circuit is not broken untilrelay 107 deenergizes which occurs-when the slow-acting release relay101 deenergizes: and sincere lay 106 is made slow-acting it retainsitsarmature until after thereleasemagnethas restored the sideswitchwipersto normal-' positionand the wiper switching relay 108 hasdeenergized.

In. the operation of the system'as 'ju'st'described theautomatic ringingof the called subscriber is started immediately' upon connection beingcompleted =to his line,'-and this is the -usual'o'pera tion. If "theoperator so 'desires however; she

can call a "subscriber v withoutfhav ing" {the signaling operation'startat" oncerand it'is'this option which the operator h'as 'of eitherautomatically ringing the called'party immediately upon connection beingestablished, or oi deferring the ringing operation" until later,whenitfmaybe started at will,- which is theprincipalfeature of myinvention. It occurs quite frequentlyflthat the, operator in order tosave time will flndit convenient to establish the local connection overthe service trunk while waiting forthe party in the distant exchange toanswer histelephone.

"Not knowing the length of time which will be.

required for an answer'to be obtainedyand in cases where a particularperson is wanted, not

being atall certain that suchfla person will be immediately accessibleby telephone, the opera-" tor will not wish to have the local partyywith whom connection is established viathe service" trunk, signalled "atoncej' for if "he answered before the required distant connectionwasready',

it might benecessary to havewait for an unreasonable length of time, oreven-to have him hang up his receiver again. In such cases as these thenit is extremely'desirable thatthe op- 1 erator should beable toestablish connection with a called line and defer the signalingoperation until the'desired toll connection is ready. When the operatordesires to postpone the automatic ringing of the called subscriber shedials the number substantially as previously described, ex cept that herlistening key K is not'actuated. It follows therefore, that when thecalling device is operated'the're is no circuit closed for the relay 3.in the cord circuit, and no ringing impulse from the generator Gen isprojected over the trunk line conductors by the operation of relays 3and 4 when the calling device returns to normal, as is the case when thelistening key isin operated; position. Consequently the alter-" natingcurrent relay 33 in the toll second selec-' tor W is not actuated tocause'the energization of 'relay 26, the latter relay thereforeremaining deenergized. Thebattery B not being disconnected from thewiper 91, as soon as the connection is extended to the connector therelay' 107 will be energiaedto disconnect the ringing apparatus, fromwhich it follows that when the connection is completed no ringingoperation will take place. Under these circumstances, when the operatorgets ready to signal the localsubscriber she will throw her key K toringing position momentarily, thereby manually projecting an impulse ofringing current out'over the trunk line. The alternating current relay33 now responds as previously described to energize relay 26,resultingin the disconnection of battery 13 from thecircuit of relay 107in the connector H.

Relay lfl'ltherefore, deenergizes and the signalling circuit is closedover the path previously traced.

Ithas been'mentioned before that the toll secconnector H,'one-of whichsets is shown at'the upper left hand corner of Fig. 2. These trunkingarrangements, together with the operation of the toll second-selectorandof the connector H when seized by a toll selector repeater and by alocal secondselector, respectively, have been described fully in myprior referred to.

Having described my invention what I consider to be new and desire tohave protected by Letters Patent will be pointed out in the appendedclaims.

What I claim as my invention is:

application previously 1. In a telephone system, a called telephoneline, operator controlled automatic switching mechanism for extending aconnection to said line, automatic ringing equipment for signalling thecalled subscriber upon the completion of the connection, manualapparatus at the operators position, and circuit connections whereby thestarting of said ringing equipment is made dependent upon the positionof said apparatus.

3. In a telephone system, means including an operators cord circuit forconnecting a calling and called line, means outside the cord circuit forsignalling the called subscriber, comprising also means forautomatically starting the signalling operation upon the completion ofthe connection, and means within the cord circuit operated prior to theestablishment of the connection for determining whether or not saidstarting means will be operated.

4. In a telephone system, means including an operators cord circuit forconnecting a calling and called line, means outside the cord circuit forsignalling the called subscriber, comprising also means forautomatically starting the signalling operation upon the completion ofthe connection, means within the cord circuit operated prior to theestablishment of the connection for determining whether or not saidstarting means will be operated, and means whereby it the said startingmeans is not operated at once it may be operated subsequently at thewill of the operator.

5. In a telephone system, means comprising a selector switch and aconnector switch for extending a connection to a called line, automaticringing equipment individual to the connector switch for signalling thecalled subscriber, and a relay in the selector switch responsive to theremoval of the receiver on the called line for stopping the signallingoperation.

6. In a telephone system, means comprising a selector switch and aconnector switch for extending a connection to a called line, automaticringing equipment, a ringing relay in said connector having contacts forconnecting said ringing equipment with a conductor of the saidconnection to the called line to form a signalling circuit, said circuitincluding a trunk conductor extending between said switches, and a relayin the selector also included in said circuit, and means for operatingsaid ringing relay to cut oil the ringing cun'ent from the called line.

'7. In a telephone system, means comprising a selector switch and aconnector switch for extending a connection to a called line, automaticringing equipment, a relay in said connector having contacts connectingsaid ringing equipment with a conductor of the connected called line toform a signalling circuit, said circuit including a trunk conductorextending between said switches, a relay in the selector also includedin said circuit, said last relay being responsive to the removal of thereceiver on the called line, and a circuit for said first relaycontrolled by said last relay whereby upon the response of the calledsubscriber said first relay is controlled to disconnect the said ringingequipment.

8. In a telephone system, a trunk line, automatic switching mechanismforextending said trunk line into connection with a called telephoneline, apparatus for automatically and intermittently signalling thesubscriber on the called line, and a relay in bridge of the theconductors of said trunk line and responsive to currents projectedthereover for starting the operation of said'signalling apparatus, and acondenser in the energizing circuit ol. said relay in series therewithand with the source of current.

9. In a telephone system, a trunk line, automatic switching mechanismfor extending said trunk line into connection with a called telephoneline, apparatus for automatically and intermittently signalling thesubscriber on the called'line, means for projecting ringing current overthe conductors of said trunk line, and an alternating current relay inbridge of said conductors and responsive to said current to start theoperation of said signalling apparatus.

10. In a telephone system, a trunk line extending from an operators cordcircuit and terminating in an automatic switch, a calling device forproducing current impulses in one conductor of said trunk line tooperate said switch, and means in the cord circuit automaticallycontrolled by the operation of said calling device to transmitringing-current over other conductors of said trunk line.

11. In a telephone system, a trunk line extending from an operatorsposition and terminating in an automatic switch, a calling device forproducing current impulses in a conductor 01' saidtrunk line to operatesaid switch, and means eifective each time the calling device isoperated to automatically project ringing current over said trunk line,said means including'a quick and a slow relay.

12. In a telephone system, a trunk line extending from an operatorsposition, automatic switching mechanisms operable in response to aplurality of operations of a dial for extending said trunk line to theline of a called subscriber, a calling device at the operators positionfor controlling the operation of said switching mechanisms, andautomatic means controlled in the operation of said calling device uponthe first dial operation for projecting'ringing current over said trunkline when all the dial operations are completed.

13. In a telephone system, means comprising selector switches andconnector switches for extending connections to called lines, automaticringing equipment individual to each connector switch for signalling thecalled subscribers, and a relay individual to each selector switchresponsive to the removal of the receiver on the called line forstopping the signalling operation.

14. In a telephone system, aselector switch and a connector switch forconnecting calling and called lines, a ringing relay in the connectorfor applying ringing current to the called line, a cut oif relay in theselector operated when the called subscriber answers for controlling theoperation of said ringing relay to cut of! the ringing current to thecalled line.

"15. In a" telephone system,' a selector switch having alternative-setsor incoming terminals, means for seizing either set or terminalsaandmeans operative according to the set of terminals seizedjto,automatically project signaling current, or not automaticallyproj'ect'signaling current from said selector.

16. In a telephone system, a selector switch having alternative sets ofincoming terminals, and means'operative toefiect automatic ringingcontrol or not effect automatic ringing control by said selectoraccording to the set of terminals connectedwithj 17. In a,j telephonesystem, an automatic switch which will junction as a selector, 9)ringing current source, alternative sets of terminals leading in to thesaid switch, called lines,,m'eans for seizing the said switch througheither set of terminals at will, means for directing the switch forseizing a called'line', means operable when a specific one ofthe sets ofsaid terminals is seized forcausing ringing current to be projected on acalled line, and means operable when a specific one of, the said sets ofterminals is.

seized whereby ringing current is not projected on a called line. I

18. man automatic telephone system, a switch which will functionas aselector, alternative sets of incoming terminals for the switch, a

source of signaling current in the switch, means for seiz'ng either setof terminals by an antecedent switch, and means respectively operativeaccording to the set of terminals seized to adapt the switch to projectsignaling current from the said source or not project signaling currentto a connected line.

19. In a telephone system comprising a local trunking system for use bylocal subscribers and a toll trunking system for use by toll operators,

a final connector switch commonto bothtrunking systems, meansforoperating said switch to complete a local connection or a tollconnection to a called line, automatic ringing equipment normallyconnected to automatically ring the called line connected with in eithertype of connection, means for automatically disconnecting said ringingequipment during the establishment of the toll connectionwhilepermitting the same to remain connected to'startthe automaticringing at once when the local connection is established, and meansbrought into use during the toll connectionfor again connecting saidringing equipment under operator control to start the automatic ringing.v t

20. In a' telephone'system comprising a local trunking system for use bylocal subscribers and a toll trunking system for use by toll operators,a final connector switch common to both trunking systems, means foroperating said switch to complete a local connection or. a tollconnection to a called line, automatic ringing equipment normallyconnected to. automatically ring the called line connected with ineither type of connection, means for automatically disconnecting saidringing equipment during theestablishment of the ,toll connection whilepermitting the same to, remain connectedtostart the automatic ringing atonce'whenthe local connection is established, and means controlled by anoperator after the toll connection is established for disabling saidringing equipment disconnecting means in order to start the automaticringin at will.

21. In a telephone system com 4, trunking System use y local subscribersand a toll trunking system for use by tolloperator's, a final connectorswitch common to both trunking systems, means for operating said switchto complete a local connection or a toll connection to a called line,automatic ringing equipment normally connected to automatically ring thecalled line connected with in either type of conscriber on the called.inecan stop the automatic ringing when he answers,. regardless ofwhether the connection to his line is"a 'toll'or a'local con-'" nection.

22. In a telephone system comprising a local trunking system for use bylocal subscriber and a toll trunking system for use by toll operators, afinal connector switch common toboth trunk ing systems, means, foroperating saidswitch to complete a local connection or a toll connectionto a called line, automatic ringing equipment normally connected toautomatically ring the called line connected with in either typeofconnection, means for automatically disconnecting said ringing equipmentduring the establishment of the toll connection while permitting thesame to remain connected to start the automatic ringing at once when thelocal connection is established, means controlled by an operator afterthe toll connection is established for disabling said ringing equipmentdisconnecting means in order to start the automatic ringing at will, andmeans whereby the subscriber onithe called line can stop the automaticringing when he answers, regardless of whether the connection to hisline is a toll or a local connection.

23. In a telephone system, a subscribers line, a switch controlled by anoperator for connecting with said line, a relay in said switch, aringing circuit including normally closed contacts of said relay, meansfor automatically energizing said relay during the establishment of theconnection to open said ringing circuit before the connection iscompleted, operator controlled meansfor deenergizing said relay to closesaid ringing cir-' cuit, and means controlled by the subscriber on thecalled line for again energizing said relay to open said ringingcircuit.

24. In a telephone system, a subscribers line, a switch controlled by anoperator for connecting with said line, means for ringing the calledline, ringing prevention means operated automatically during theestablishment of the connection for rendering said ringing meansinefiective, operator controlled means operable at any time after theconnection is completed for restoring said ringing prevention means tocause the said ringing means to become effective to signal the calledline, and means controlled by the subscriber on the called line foragain operating said ringing prevention means to stop the signallingoperation.

25. In a telephone system, a subscribers line, I

an operators switchboard, means including an automatic switch forextending a connection from said switchboard to said line, automaticringing automatically signal the called line, and means controlled bythe subscriber on the called line for again energizing said relay tostop the signalling operation when the called subscriber answers.

26. In a telephone system, a subscriber's line, an operatorsswitchboard, means including an automatic switch for extending aconnection from said switchboard to said line, automatic ringingequipment, a relay in said switch energized before the operation of saidswitch is finished in order to prevent said equipment from signallingthe called line when the connection thereto is completed, meanscontrolled by the operator at said switchboard for deenergizing saidrelay to cause said ringing equipment to automatically signal the calledline, and means controlled by the subscriber on the called line foragain energizing said relay to stop the signalling operation when thecalled subscriber answers.

27. In-a telephone system, a calling station, a telephone line involvingnear and remote sections thereof, a junction point of the sections, afirst relay controlled from the remote section and a second relaycontrolled from the near section together operative to join the sectionsat the junction point, first and second signalling current sources, saidfirst source being of a character erate the second relay to apply thesecond source to the remote section after the last directive operationhas been transmitted to the selective switch mechanism, and a circuitconnection madeoperative consequent to the operation of the second relaywhereby the first relay will become in control of the remote section tojoin the sections.

28. In a telephone system, a calling station, a telephone line involvingnear and remote sections thereof, a junction point of the sections, afirst relay controlled from the remote section and a second relaycontrolled over the near section together operative to join the sectionsat the junction point, first and second signalling current sources, saidfirst source being of a character to which a condenser is transparent,the second relay responsive to the first source applied overthe nearsection to apply the said second source to the line, and to prepare anoperative circuit pathfor controlling the first relay for joining thesections, selective switch mechanism, means for directively operatingthe selective switch mechanism to complete a connection from the callingstation to include the line, means for initially applying the firstsource over the near section after the last directive operation has beentransmitted to the selective switch mechanism to apply the second sourceto the remote section and to prepare the said circuit path for the firstrelay, whereby the first relay will become in control of the remotesection to join the sections.

29. In a telephone system, a calling station, a telephone line involvingnear and remote sections thereof, a junction point of the sections, afirst relay controlled from the remote section and a second relaycontrolled over the near section together operative to join the sectionsat the junction point, first and second signalling current sources, thesecond relay responsive to the first source applied over the nearsection to apply the said second source to the line and to prepare anoperative circuit path for controlling the first relay for joining thesections, selective switch mechanism, means for directively operatingthe selective switch mechanism to complete a connection from the callingstation to include the line, means for initially applying the firstsource over the near section after the last directive operation has beentransmitted to the selective switch mechanism to apply the second sourceto the remote section and to prepare the said circuit path for the firstrelay, whereby the first relay will become in control of the remotesection to join the sections, and disconnect the said relays from theconnection.

30. In a telephone system, a calling and a called line, automatic switchmechanism for connecting said lines, a source of signaling current forapplication to the called line, a source of inductive current, means forat will applying the inductive current over the calling line after thesaid lines are connected for applying the signaling current to thecalled line, and automatically applied means for maintaining the saidapplication of thesignaling current.

31. In a telephone system, a calling and a called line, automatic switchmechanism for connecting said lines, a source of signaling current forapplication to the called line, a source of inductive current, means forat will applying the inductive current over the calling line after thesaid lines are connected for applying the signaling current to thecalled line, and automatically applied means for maintaining the saidapplication of the signaling current regardless of the termination ofthe application of the inductive current.

32. In a telephone system, a calling and a called line, automatic switchmechanism for connecting said lines, a source of signaling current forapplication to the called line, a source of inductive current, means forat will applying the inductive current over the calling lineafter thesaid lines are connected for applying the signaling current to thecalled line, automatically applied means for maintaining the saidapplication of the signaling current regardless of the termination ofthe application of the inductive current, and means on the called linefor terminating the application of the signaling current.

33. In a telephone system, a calling and a called line, automatic switchmechanism for connecting said lines, a source of signaling current forapplication to the called line, another source of current, means for atwill applying the said another source of current over the signaling lineafter the said lines are connected but before any operation hasthereafter occurred on the called line for applying the signalingcurrent to the called line, and automatically applied means formaintaining the said application of the signaling current. I

34. In a telephone system, a calling and 2. called line, automaticswitch mechanism for connecting said lines, a source of signalingcurrent for application to the called line, another source of current,means for at will applying the said another source of current over thetalking conductors of the calling line after the said lines areconnected but before any operation has thereafter occurred on thecalling line for applying the signaling current to the called line, andautomatically applied means for maintaining the said application of thesignaling current.

35. In a telephone system, a calling and a called line, automatic switchmechanism for connecting said lines, a source of signaling current forapplication to the called line, another source of current, means for atwill applying the said another source of current over a talkingconductor of the calling line after the said lines are connected butbefore any operation has thereafter occurred on the called line forapplying the signaling current to the called line, and automaticallyapplied means for maintaining the said application of the signalingcurrent.

36. In a telephone system, a calling line, a called line, switchingmechanism for extending a connection from the calling line to the calledline, a source of signaling current for application to the called line,a source of current to which a condenser is transparent, operatordirected means controlled over the calling line for operating theswitching mechanism to extend a connection from the calling line to thecalled line, operator directed means for thereafter at will applying thesecond said source of current over the calling line effective to firstapply first said source of current to the called line, automaticallyapplied means for maintaining the application of current to the calledline, and means controlled over the called line for disabling the saidautomatically applied means.

37. In an automatic telephone system, a called line, first and secondcalling lines, automatic switches for linking connections from therespective calling lines to the called line, a connective switch of saidswitches for completing connections to the called line common toconnections from said calling lines to the called line, a selectiveswitch of said switches for completing connections to the connectiveswitch common to connections from the said calling lines to the calledline, specific selector switches for completing connection from therespective said calling lines to the selective switch, and meansinvolving one of said selector switches depending upon which saidcalling line is extended to the connective switch for determining whatspecific operation the connective switch will be enabled to thereafterperform.

38. In a telephone system, a called line, a first automatic switchhaving selective access to the called line, a second automatic switchhaving selective access to the said first switch, calling lines, switchelements for extending connection from a random one of said callinglines to said second automatic switch, the calling line determiningwhich of said elements will be employed in the extension, meansthereupon operable over the said extension from the random calling lineapplied through the concerned said element and said second automaticswitch for selectively opcrating said first automatic switch to selectthe called line, and means the operation oi which is determined by theparticular said element em ployed in the extension to the said firstautomatic switch for determining what particular variable behavior saidfirst automatic switch will be en-- abled to manifest.

3&9. In a telephone system, a called line, a first automatic switchhaving selective access to the called line, a source of signallingcurrent for 8 application to the called line, a second automatic switchhaving selective access to the said first switch, calling lines, switchelements for extending connection from a random one of said callinglines to said second automatic switch, the calling line determiningwhich of said elements will be employed in the extension, meansthereupon operable over the said extension from the random calling lineand through the concerned said element and said second automatic switchfor selectively operating said first automatic switch to select thecalled line, and means the operation of which is determined by theparticular said element employed in the extension to the said firstautomatic switch for determining whether or not said source ofsignalling current will be applied to the selected called lineresponsive to said selection.

40. In a telephone system, a called line, a first automatic switchhaving selective access to the called line, a second automatic switchhaving selective access to said first switch, calling lines, means forextending connection from the respective calling lines to the saidsecond switch in a different manner specific to the calling lines, meansfor extending connection from a random one of the calling lines to thecalled lines wherein the first and second switches are links in theconnection, and means depending upon from which said calling line theconnection is extended from for determining what behavior the said firstswitch will be enabled to manifest.

41. In a telephone system, a called line, a first automatic switchhaving selective access to the called line, a second automatic switchhaving 120 access to the said first switch, a plurality of otherswitches having selective access to the said second switch, a pluralityof leading-in paths to said second switch, means for extendingconnection over a random one of said plurality of paths to 25 manifest.

JOHN WICKS.

